Starting motor switch



Nov. 10, 1931.

L. S. SHELDRICK STARTING MOTOR SWITCH Filed March. 12. 1930 INVENTOR.

A TTORNE Y.

pitted due to the arcing.

Patented Nov. 10, 1931 UNITED STATES LAWRENCE S. SHELDRICK, OF.DETROIT,MICHIGAN, ASSIGNOR TO FORD MOTOR COM PANY, OF DEARBORN, MICHIGAN, ACORPORATION OF DELAWARE r s'ran'rme oron swrron Application filed Marc'hl2, 1930. Serial No. 435,066.

The object of my invention is to providea starting motor switch ofsimple, durable, and inexpensive construction.

A further object of my invention 1s to provide a starting motor switchespecially adapt-.

ed for use with the automobile starting motors. In the ordinaryautomobile, the starting motor is supplied with current from a sixvoltbattery, one terminal of the battery being grounded while the otherterminal is connected with the starting motor switch which in turnconnects with the starting motor. Due to the low voltage used, thiscurrent frequently runs as high as 200 amperes so that the startingmotor switch must be able to operate under these severe conditions. Ifthe ordinary knife type switch were used, it would be quite costly andfurther, would not be convenient for the driver to operate; while if asimple-non-sliding push type switch were used the switch points wouldsoon become I have provided a switch in which an initial sliding actionis obtained over a rather small area which is increased to a larger areaas the switch is further applied. The large area carries the currentnormally used to operate the starting motor, while at the same time theare produced when the switch is broken is restricted to a relativelysmall area over which a limited sliding action occurs to thereby preventpitting of the switch contacts. I have thus obtained the desirablefeatures of the knife type switch together with the simplicity of thepush type switch.

Still a further object of my invention is to provide a starting switchhaving a relatively simple and inexpensive equalizing link extendingbetween the movable switch member and the switch applying member.

With these and other objects in view my invention consists in thearrangement, construction, and combinatlon of the various parts of myimproved dev1ce,'as descrlbed in the specification, claimed in myclaims,

and illustrated in the accompanying drawings, in which;

Figure 1 shows a side elevation of a starting motor having my improvedstarting motor switch mounted thereon, the switch being shown in sectionto better, illustrate the construction.

Figure 2 shows a sectional view taken on the line 2-2 of Figure 1. l

Figure 3v shows a diagrammatic view of the various positions assumed bythe switch member before full engagement, and

.Figure 4 shows the position assumed by PATENT 'QOFFICE.

the switch-member when'the switch is fully engaged.

Referring to the accompanying drawings, I haveused the reference numeral10 to indicate generally an automobile starting mo tor. This motor isgenerally secured toan engine fly wheel housing in position forwardlyand "beneath the front floor boards of the automobile. A terminal issecured in the upper body'of the starting motor 10 and is insulatedtherefrom bymeans of insulation- 12. A head 13 is formed on the outerend of this terminal which forms one of the contacts of my improvedswitch.

I have provided an inverted cup shaped housing 14 which is fastened byscrews 36 to the motorlO above the terminal 11 and whichis preferablypressed from relatively light sheet metal. A'switch blade 15 is securedat one end in the rear portion of the housing 14; by means of a terminalbolt 16 and insulation 17. The insulation member 17 is of square sectionand extends through a correspondingly squared opening in the hous ing tothereby be non-rotatably secured. A portion of the bolt 16 adjacent toits head is also squared at 18 and extends through correspondinglysquared openings'in'the blade 15 and insulation 17. i

It may thus be seen that the blade 15 is prevented from rotating aroundthe bolt 16 independently of the clamping force of the bolt. A sheet ofinsulating paper 19 is fa stened in the housing 14 by engagement withthe bolt 16, and extends within the top and side portions of thehousing. Thus, if'the ioo thereof, this terminal being fastened ontothebolt' 16 by means of a lock nut 23.

The free end of the blade is disposed di rectly over the head so that itmay be flexed downwardly into contact with this head to complete theelectrical circuit therebet-ween.

Means are provided for flexing this blade which consists of a coupling24, operating rod 26, and equalizing link 30. The coupling 24: isreciprocally mounted in a suitable opening 25 formed in the upperportion of the housing 14: and the rod 26 is threaded into the upper endof this coupling and extends in a diagonal direct-ion up through thefloor boards of the car, these boards being illustrated by dotted lines27. A head 28 is formed on the upper end of the rod 26 in position to beconveniently depressed by the driver of the car.

The lower end of the coupling 2& is provided with an axial bore 31 intowhich the link is loosely fitted. This link is preferably stamped from asheet of fibre but, if desired, it may be turned or formed by othermeans from any insulation material. The

. lower end of the coupling 2a is flanged outwardly to form a stopwhereby the upward movement of the coupling will be limited.

The free end of the blade 15 extends forwardly from the bolt 16 and isbent back upon itself at 29 wherein an opening 37 is provided to receivea detent 32 formed on the lower end of the link 30. That portion of thelink adjacent to the detent 32 is enlarged so that it may co-act withthe bent portion 29. It may thus be seen that when the rod 26 isdepressed it forces the link 30 downwardly whichv brings the blade 15into contact with the head 13 to complete the electrical circuit. Itwill be noted thatthe blade 15 is flexible andthat the free end bends inan arcuate path around the bolt 16 while the coupling 24 reciprocates ina straight path through the opening 25. The function of the link 30 isto convertthereciprocating movement of the coupling into an arcuate pathso that there will be no sliding action between the parts.

Referring to Figure 3, I have-shown the shape normally assumed bythe-blade 15 when removed from the housing 1&1 by the dotted lines 35.It will be seen that this blade is bowed upwardly at 38, adjacent to thesection clamped by the bolt 16, and that the outer end is bentdownwardly at 39 intermediate of its ends. When the blade is as sembled.in the housing it is deflected into with the terminal head 11.

the position shown by solid lines 33 by the link 30 so that rattlebetween the parts is entirely eliminated and so that the blade will atall times be resiliently held in its inoperative position.

Aslthe head 28 is depressed the blade 15 first assumes the position,shown by dotted lines 3 where an initial contact is made by the extremeforward end of the blade with the terminal head 11. A further depressionof the head 28 forces the end of the bent portion 29 into contact withthat portion of the bladeadj-acent to the bowed portion 39 so that thebladeis flattened into full contact This fully engagedpositionisillustrated in Figure 4:. It maybe seen that as the blade is thusflattened its point of initial contact or extreme forward end is forcedto slide a short distance along the terminal head. This sliding actionis very desirable as it tends to remove any pitting scale from thepoints of initial contact.

When the head 28 is released, the center portion of the blade firstpulls away from the terminal head and assumes the position shown at 34,and then the extreme forward end is drawn away. The arcing which resultswhen the current is broken always takes place at the forward end oftheblade and,

as this end is kept clean by the above described sliding action, a flowof current is.

always assured when the switch is operated. The main portion of thecontactsalways remain clean because the arcing .is restricted to theforward portion of the contacts.

Among the many advantages arising from the use of my improved device, itperhaps should be. repeated that I have provided a switch in which theare produced when the switch isbroken is restricted to a relativelysmall area over which a limited sliding action occurs to therebypreventpitting of the switch contacts. I have thus obtained the desirablefeatures of the sliding knife type switch together with the simplicityof con-r struction of the push type switch.

Somerchanges may be made in the arrangement, construction, andcombination of the various parts of my improved device without departingfrom the spirit of my invention, and it is my intention to cover by myclaims, such changes as may reasonably be included within the scopethereof.

, I claim as my invention:

1. In a switch, a terminal, a switch blade having one end fixedlyanchored and the other end arranged to arcuately flex into contact withsaid terminal, a reciprocc ting operating means, and a link disposedbetween the operating means and the free end of said blade wherebysliding action between the blade and link and operatingmeans, due to thevariance between said reciprocating and arcuate movements, iseliminated.

2. In a switch, a terminal, a switch blade having one end fixedlyanchored and the other end arranged to arcuately flex into contact withsaid terminal, a reciprocating operating means, and a link of insulatingmaterial disposed bet-ween said operating means and the free end of saidblade whereby slidingaction between the blade and link and operatingmeans, due to the variance between said reciprocating and arcuatemovements, will be eliminate 3. In a switch, a terminal, a switch bladehaving one end fixedly anchored and the other end arranged to arcuatelyflex into contact with said terminal, an operating rod mounted toreciprocate axially, one end thereof being adjacent to the free end ofsaid blade, a coupling secured to said adjacent end having an axial boretherein, and a link loosely mounted in said bore and projecting there-'from to the free end of said blade, whereby sliding action between theblade and link and coupling, due to the variance between saidreciprocating and arcuate movements, will be eliminated.

4. In a switch, a terminal, a switch blade having one end fixedlyanchored and the other end arranged to arcuately flex into contact withsaid terminal, an operating rod mounted to reciprocate axially intocontact with said terminal, one end thereof being adjacent to the freeend of said blade, a coupling secured to said adjacent end having anaxial bore therein, a link of insulating material loosely mounted insaid bore and projectingtherefrom to the free end of said blade, wherebysliding action between the blade and link and coupling, due to thevariance between said reciprocating and arcuate movements, will beeliminated.

5. In a switch, a terminal, a switch blade having one end fixedlyanchored and the other end arranged to arcuately flex into contact withsaid terminal, an axially reciprocating operating means having one endadjacent to the free'end of said blade, said adjacent end having anaxial bore therein, a link of insulating material loosely mounted insaid bore and projecting therefrom to the free end of said blade,whereby sliding action between the blade and link and'operating means,due to the variance between said reciprocating and arcuate movements,will be eliminated.

6. In a switch, a terminal, a switch blade arranged to arcuately flexinto contact with said terminal, an axially reciprocating operating rodextending diagonally from the free end of said blade and in the plane ofsaid flexing movement, and an insulating link disposed between said rodand free end of said blade, whereby the diagonal reciprocating movementof the operating rod will arcuately flex the switch blade while slidingaction between these parts is eliminated.

7. In a switch, a terminal, a switch blade flexing movement, a couplingdisposed on the end of said rod adjacent to the switch blade,

said coupling having an axial bore therein aligned with the openin insaid blade, and an insulating link exten ing into said opening and boreand loosely mounted in each, whereby the diagonal reciprocating movementof the operating rod will arcuately flex the switch blade while slidingaction between these parts is eliminated.

8. In a switch, a terminal, a bowed switch blade having one end fixedlyanchored and the other end arranged to arcuately flex into contact withsaid terminal, and means for initially applying the free end of saidblade into contact with a portion of said terminal, the furtherapplication of which applying means flattens the blade therebyincreasing its effective length and producing a sliding action over theinitial area of contact while enlarging the contact area to the fullarea of the terminal.

9. In a switch, a terminal, a bowed switch blade having one end fixedlyanchored and the other end arranged to arcuately flex into contact withsaid terminal, an operating rod mounted to reciprocate axially, one endthereof being adjacent to the free end of said blade, a coupling securedto said adjacent end having an axial bore therein, and a link ofinsulating material loosely mounted in said bore and projectingtherefrom to the free end of said blade, whereby initial actuation ofsaid rod applies the free end of said blade into contact with a portionof said terminal and further application of the rod flattens the bladethereby increasing its eflectivelength to produce a sliding action overthe initial area of contact, said link compensating for the variancebetween the arcuate movement of the blade and the reciprocating movementof the rod to thereby unefi'ect the sliding action of the initial areaof contact.

10. In a switch, an inverted cup-shaped housing, a switch blade, a boltextending through suitable aligned openings in one end of said blade andhousing and insulated from the latter, a terminal mounted to enter theopen end of said housing in position whereby the blade may be arcuatelyflexed into contact with said terminal, an operating rod reciprocallymounted in the bottom of said housing adjacent to the free end of saidblade, and a link disposed between the free end of said blade and saidoperating rod, said blade being so initially formed that it must bepartially flexed when in its inoperative position, thereby preventingrattle between the blade and link and operating rod and housing.

